Ultrasensitive Dual-Signal Detection of Telomerase and MiR-21 Based on Boolean Logic Operations.

Telomerase and micro-RNAs (miRNAs) are simultaneously upregulated in a variety of tumor cells and have emerged as promising tumor markers. However, sensitive detection of telomerase and miRNAs in situ remains a great challenge due to their low expression levels. Here, we designed a Boolean logic "AND" signal amplification strategy based on functionalized ordered mesoporous nanoparticles (FOMNs) to achieve ultrasensitive detection of telomerase and miR-21 in living tumor cells. Briefly, the strategy uses telomerase as an input to enable the release of DNA3-ROX-BHQ hairpins by making the wrapping DNA1 form a DNA-a hairpin with the joint participation of dNTPs. Subsequently, DNA2-Ag, DNA3-ROX-BHQ, and the second input miR-21 participated in hybridization chain reaction to amplify fluorescence and Raman signals. Experimental results showed the intensity of output dual signals relevant to the expression levels of telomerase and miR-21. The Ag nanoparticles (AgNPs) not only enhanced the fluorescence signals but also allowed to obtain more sensitive Raman signals. Therefore, even if expression of tumor markers is at a low level, the FOMN-based dual-signal logic operation strategy can still achieve sensitive detection of telomerase and miR-21 in situ. Furthermore, FOMNs can detect miR-21 expression levels in a short time. Consequently, this strategy has a potential clinical application value in detection of tumor markers and the assessment of tumor treatment efficacy.

A versatile two-photon fluorescent probe for ratiometric imaging E. coliß-galactosidase in live cells and in vivo.

We have described the design, synthesis, spectroscopy and biological applications of NI-ßGal, a versatile fluorescent probe to detect E. coliß-galactosidase in live cells and mice sensitively and directly, which holds great promise for its application in biomedical research such as gene therapy for cancer in the future.

A turn-on fluorescent chemodosimeter based on detelluration for detecting ferrous iron (Fe2+) in living cells.

A turn-on fluorescent probe for the detection of Fe2+ is facilely synthesized via a nucleophile substitution reaction. The fluorescent probe, N-butyl-4-phenyltellanyl-1,8-naphthalimide (Naph-Te), shows excellent selectivity to Fe2+ in a mixed solution of acetonitrile and phosphate buffer under aerobic conditions. The coexistence of biological abundant metal ions such as Na+, K+, Ca2+ and Mg2+ has little effect on the fluorescence signal. This turn-on response is achieved via a redox-involved reaction triggered by Fe2+ at neutral pH and room temperature, which removes the heavy-atom effect of the tellurium atom on the naphthalimide fluorophore to afford a fluorescent product (N-butyl-4-hydroxyl-1,8-naphthalimide). The probe has excellent cell membrane permeability and is further applied successfully to monitor supplementary Fe2+ in live HL-7702 cells using a laser confocal fluorescence microscope.